Try as DaiNasty said, a bootable CD can be really effective, just make a note if possible about what is being removed.

Alternatively you could try a couple of other on-demand scans, or maybe try asquared cloud scanner
http://www.emsisoft.com/en/software/ax/?scan=1 (needs Internet Explorer to run as ActiveX is used, also be aware of what is being quarantined/removed), or the full free edition
http://www.emsisoft.com/en/software/free/
Maybe also try SuperAntiSpyware
http://www.superantispyware.com/ or Bitdefender Free
http://www.bitdefender.com/PRODUCT-1...e-Edition.html.
Do you not have the option to use a recovery console or the ability to format the drive and clean install? Sometimes when something is so ingrained in can be nigh on impossible to remove for sure!
Possibly also register somewhere like
http://www.bleepingcomputer.com/ where someone can guide you through using other methods such as Combofix, Rootkit removal, etc.
Back up any important stuff you know is ok before removing items